docs: def _set_asset_paths(self, app):
          """
          Read in the manifest json file which acts as a manifest for assets.
          This allows us to get the asset path as well as hashed names.
  
          :param app: Flask application
          :return: None
          """
          webpack_stats = app.config['WEBPACK_MANIFEST_PATH']
  
          try:
              with app.open_resource(webpack_stats, 'r') as stats_json:
                  stats = json.load(stats_json)
  
                  if app.config['WEBPACK_ASSETS_URL']:
                      self.assets_url = app.config['WEBPACK_ASSETS_URL']
                  else:
                      self.assets_url = stats['publicPath']
  
                  self.assets = stats['assets']
          except IOError:
              raise RuntimeError(
                  "Flask-Webpack requires 'WEBPACK_MANIFEST_PATH' to be set and "
                  "it must point to a valid json file.")